1. The Field of the Invention
This invention relates to hand-operated mechanisms for controlling and securing lines and more particularly it relates to devices which will releasably secure a line in a desired position when hauling in or paying out a line under load.
2. Description of the Prior Art
Hand operated devices for controlling and securing lines that are payed out or hauled in under load are known to the prior art and have been used for a number of purposes. For example, in my prior U.S. Pat. No. 4,546,851, I disclose a device to aid a person, such as a deer hunter, in climbing a tree. Essentially this device, as is true of many others, provides means for the attachment of a harness or seat to the standing part of a line in combination with a mechanical hand operated locking device that engages the running part of the line as well as a harness or seat. The locking device is of a toothed cam sort that permits the line to move through the device in one direction but locks up and prevents the line from moving in the other direction. Because of this locking feature, the climbers seat or harness is held secure at any elevated position.
One deficiency in the type of climbing device shown in my patent, as is common with many others, is that no provision is made for paying out rope. The only way in which a climber may descend is to disengage the line from the device and then lower himself hand over hand.
A related device is illustrated in U.S. Pat. No. 4,217,847. Here is shown a so-called cam cleat for securing nautical lines, such as sail sheets. The salient feature of this device is a smooth release cam surface which allows a line under load to be released without having to haul in on the line to disengage the line from the cleat.
Other hand operated devices for controlling lines under load have been designed primarily for use with fire escape devices. Illustrative of these is U.S. Pat. No. 259,279 which describes a device which can be used by a person to lower himself from an elevated location. Note that it can not function to aid a person in climbing.
Some prior art devices of the type with which this invention is concerned are inconvenient to use because an end of the line must be threaded through the device, which is more difficult than engaging or disengaging the bight of a rope.
Those devices known in the prior art that permit a person to descend a rope usually have some sort of hand triggered mechanism that, when squeezed, will rotate toothed cams away from engagement with the rope and allow the person to descend. While this arrangement operates well as long as the user understands what he is doing, it is possible, as in a moment of panic when descending too rapidly, to clutch the trigger mechanism harder and lose all control over the rate of descent.